Chromium Blog: September 2015

Chrome 46 Beta: Flexible animations and improved loading performance

Wednesday, September 2, 2015

The newest Chrome Beta channel release includes new CSS animation features, improved performance controls, and a large number of API tweaks. Unless otherwise noted, changes described below apply to Chrome for Android, Windows, Mac, Linux, and Chrome OS. Animating objects along author specified paths Previously, animating objects along an author-specified path required complex javascript code that could block important events like rendering and input. Developers can now animate any graphical object along an arbitrary path declaratively as a CSS property, allowing simpler code that doesn’t block rendering or input.
Complex animations using CSS Optimized image loading and service worker instrumentation Tools like srcset allow developers to serve an optimized image variant in a responsive way, but it can be cumbersome and inefficient to use in practice. Developers can now negotiate with the server to download the best image variant for a device using straightforward HTTP request headers. These headers communicate DPR, Viewport-Width, and the intended display width of the resource being fetched to the server.
In addition to improving image loading, developers can now instrument service workers to gather detailed fetch and script timing. Developers can also measure the startup time of service workers more accurately. Other updates in this release

As part of Chrome’s ongoing efforts to ship features from the ES2015 specification, Chrome now supports the spread operator and new.target.

To prevent user annoyance and conserve power, Chrome will now defer playback of autoplay videos in background tabs until the first time the tab is foregrounded.

Developers can now disable Chrome’s default scroll restoration behavior on history navigation when it interferes with the app’s user experience.

Sites can specify origins that Chrome should preconnect to in order to improve performance.

Sites launched from the home screen can now modify the default color of Chrome’s UI by specifying a theme color in their web manifest instead of a meta tag.

Sites that have been added to the homescreen can now set a background color to show while resources load.

Developers can now specify a URI for Chrome to report HTTP Public Key Pinning violations to, making man-in-the-middle attacks easier to find.

Events generated by user action can be differentiated from events generated by script using Event.isTrusted(), allowing developers to protect against fake clicks.

Developers can now use CSS.escape(), eliminating the need for complicated string escape code while handling user generated identifiers.

Modal dialogs are now blocked by default in sandboxed iframes, preventing embedded content from abusing APIs like alert.

Sites can now set an iframe attribute that allows sandboxed content to launch unrestricted windows.

As part of our continuing policy to remove powerful APIs on insecure origins, the Cache API is now restricted to HTTPS.

Cache.addAll() is now supported, removing the need for polyfills enabling bulk interactions with the cache.

The Fetch API now supports Request.redirect, allowing more control over redirects.

DOMExceptions can now be constructed from scripts, making polyfills easier to build for specs that require exceptions.

Timer-based polling is no longer necessary to use WebRTC DataChannels, making them more efficient and convenient.

DevTools now has better tool tips and custom network profiles.

Resource Timing extensions to the Performance interface are now available without prefixes.

The CSS intrinsic sizing values, which allow boxes to fit their contents, are no longer prefixed.

Request.context has been removed until the the spec has stabilized.

Posted by Eric Willigers, Software Engineer and Animations Acrobat

Chrome custom tabs smooth the transition between apps and the web

Wednesday, September 2, 2015

Android app developers face a difficult tradeoff when it comes to showing web content in their Android app. Opening links in the browser is familiar for users and easy to implement, but results in a heavy-weight transition between the app and the web. You can get more granular control by building a custom browsing experience on top of Android’s WebView, but at the cost of more technical complexity and an unfamiliar browsing experience for users. A new feature in the most recent version of Chrome called custom tabs addresses this tradeoff by allowing an app to customize how Chrome looks and feels, making the transition from app to web content fast and seamless.

Chrome custom tabs allow an app to provide a fast, integrated, and familiar web experience for users. Custom tabs are optimized to load faster than WebViews and traditional methods of launching Chrome. Apps can pre-load pages in the background so they appear to load nearly instantly when the user navigates to them. Apps can also customize the look and feel of Chrome to match their app by changing the toolbar color, adjusting the transition animations, and even adding custom actions to the toolbar so users can perform app-specific actions directly from the custom tab.
Custom tabs benefit from Chrome’s advanced security features, including its multi-process architecture and robust permissions model. They use the same cookie jar as Chrome, allowing a familiar browsing experience while keeping users’ information safe. For example, if a user has signed in to a website in Chrome, they will also be signed in if they visit the same site in a custom tab. Other features that help users browse the web, like saved passwords, autofill, Tap to Search, and Sync, are also available in custom tabs.

Custom tabs are easy for developers to integrate into their app by tweaking a few parameters of their existing VIEW intents. Basic integrations require only a few extra lines of code, and a support library makes more complex integrations easy to accomplish, too. Since custom tabs is a feature of Chrome, it’s available on any version of Android where recent versions of Chrome are available.
Users will begin to experience custom tabs in the coming weeks in Feedly, The Guardian, Medium, Player.fm, Skyscanner, Stack Overflow, Tumblr, and Twitter, with more coming soon. To get started integrating custom tabs into your own application, check out the developer guide.
Posted by Yusuf Ozuysal, Chief Tab Customizer

Chromium Blog

Chrome 46 Beta: Flexible animations and improved loading performance

Chrome custom tabs smooth the transition between apps and the web

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